When the Buick LaCrosse was introduced for 2010, it featured a standard V-6, with GM officials saying that a four-cylinder was on the way later that year, a relative rarity then amongst Buicks, entry-luxury sedans and full-size four-doors. The LaCrosse qualified as all of these, and though GM stressed the quiet and space of the first all-new car born of the new GM, the more fuel-efficient four still seemed pushed to the background, with no four available to test at the launch.

Fast forward to now, and GM has turned the tables 180 degrees. The 2012 LaCrosse models both feature new powertrains this year, but almost all of GM’s emphasis at this launch is on the four, which now becomes the LaCrosse eAssist. Despite adding a large 115-volt battery behind the rear seats, start/stop technology and an electric motor that boosts power to the front wheels on a regular basis, you won’t find any hybrid or even eAssist labels on the outside of this car.

The LaCrosse V-6 was also upgraded for 2012, and now uses the same direct-injection 3.6-litre, 303-hp powerplant as the Cadillac CTS. Unfortunately, none were on hand for this high-tech focused preview of the car in Silicon Valley.

The LaCrosse eAssist is the first but not the last using such technology. Close behind the LaCrosse will be an electrically boosted Buick Regal eAssist later this fall, and a similarly powered 2013 Malibu Eco next year. All will be mild hybrids, because they can’t move on electricity alone, even if GM shies away from the hybrid tag.

GM advanced battery engineer Tony Saliga says the system advances the one used in the former Malibu (mild) hybrid in a number of ways. The battery cells – the size of 32 Red Bull cans – use the same liquid coolant as the engine, with a separate radiator and coolant reservoir, in order to prevent the heat buildup in batteries that has occasionally caused problems with made laptop batteries.

The battery is a larger lithium-ion unit. Special software cuts off virtually all fuel to the engine upon deceleration and aerodynamic panels under the body are tuned for quiet as well as slipperiness through the air. There are the usual start/stop systems found on hybrids that help reduce the eAssist’s fuel appetite. It also weighs a mere six kilograms more than a 2011 LaCrosse four, but achieves up to 21 per cent better fuel economy than the outgoing four.

Compared to the LaCrosse V-6, the results are about twice as dramatic. The eAssist registers official fuel consumption numbers of 8.4 litres/100 km city and 5.4 highway, while the V-6 averages 12.1 city and 7.3 highway. Where real-world consumption numbers will land is a good question, but it’s clear that most LaCrosse eAssist buyers will make up the extra $1,015 payout over a base V-6.

The eAssist’s starting price of $35,415 may be about four grand more than the outgoing gas-only LaCrosse four, but it’s also a significant five to seven thousand less than the MSRP of its two key luxury hybrid rivals, the Lexus HS250h and Lincoln MKZ Hybrid, respectively. Those models both get significantly better official city fuel economy, but they’re also notably smaller and less artfully designed inside.

The more mainstream eAssist price also means it will better compete with mainstream products, including the base LaCrosse, which in Canada will start at $34,400. It may be the lowest premium for a hybrid version in Canada, but in the United States the eAssist comes standard on the notably lower-priced $29,960 (U.S.) LaCrosse, with the V-6 a no-cost option, similar to how Lincoln markets the MKZ there.

Using the factory fuel economy figures for the Buick and Lincoln, my rough math, and assuming a $1.30-a-litre price for the regular fuel they both take, the LaCrosse eAssist would use $1,010 more fuel a year than an MKZ Hybrid if you do all 20,000 km of your driving in city traffic.

But even hybrids are not bought purely for their fuel economy and potential cost savings, especially luxury ones. So how is the LaCrosse eAssist to drive? In a nutshell, as smooth if not smoother overall than any other hybrid, though still not as quiet, refined or nearly as powerful as conventionally powered market rivals.

Buick says eAssist adds the equivalent of 15 hp and 79 lb-ft of torque to the previously anemic 2.4-litre four, coming in seamlessly when passing or pressing on, although the four-cylinder still becomes loud at high rpm. It’s far from fleet, but more respectable now. The extra kick feels much closer to the former horsepower than the latter torque figure, both still tallying up to quite a bit less thrust than the standard LaCrosse’s V-6.

And unlike supercharged Buicks of recent times, or the turbocharged engines in some rivals, this power boost won’t cost you at the fuel pump.

So are fuel-conscious Canadians ready to pay (slightly) more for less power and refinement – compared to a regular LaCrosse V-6 – in an entry luxury class that traditionally charges more for both? GM Canada figures the majority won’t, estimating about 20 per cent of 2012 LaCrosse buyers will opt for the eAssist system. But as North America creeps closer to European fuel prices, perhaps our priorities will slowly adjust along with them.

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